Logging During Load

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AIX Versions 3.2 and 4 Asynchronous Communications Guide

Logging During Load

The log flag enables the basic input/output system (BIOS) to log load events during loader execution. This logging is useful when the 7318 is not downloading. In addition, system administrators can use the logging feature to diagnose LAN problems that may not be directly caused by the 7318. A request for the BIOS console automatically enables logging.

The BIOS has three major logging phases: discover, BOOTP, and TFTP.

Discover Logging - IPX Loads Only

The discover phase of the network load determines basic network information about available hosts and routers on the network and potentially determines the load host. The discover phase follows and logs a three-step process:

If you choose the Service Advertising Protocol (SAP) load method, the discover phase sends a find-any-server request to the network. The BIOS, upon receiving a response, has a potential load host.
```
#> load
Probing for an IPX load host
IPX load host named levesconte responded (00000011)
IPX load host named lester responded (00000001)
```
Once the BIOS receives a SAP response, the discover phase sends a series of one or more Routing Information Protocol (RIP) packets to the network. These packets request low-level information about how to reach the load host (received from the find-any-server request or from a directed load host). In this phase, the BIOS may delay for a while, after which it displays all hosts that responded to the RIP queries.
```
Attempting to resolve IPX addresses
Resolved IPX address: 00000011 at ethernet address 02608C2F15D9
Resolved IPX address: 00000001 at ethernet address 02608C2EB396
```
Finally, the discover phase advertises itself, using a SAP broadcast. The discover phase sends the following packet both when the BIOS comes up as well as every 60 seconds after that:
```
Netloader - DISCOVER 5.0
Using the AUI interface
Probing for an IPX load host
IPX external network is 00000002
IPX load host named muc2CNSLOADHOST responded (00000001)
Resolved IPX address: 00000001 at ethernet address 02608C2EB87D
Sending SAP advertisement (we are: CNS00406E0002DB_FFFFFFFF_BT)
```
Note: In the case of a User Datagram Protocol (UDP) load, the discover phase has no function. In a mixed load, the discover phase runs; however, UDP interaction only takes place in the BOOTP phase.

If there are problems in loading a 7318, the discover phase can be useful in problem determination. The determination of the Internet Packet Exchange (IPX) network number must happen; if it doesn't, the 7318 is not properly cabled to the LAN, or there are no IPX hosts sending packets on the network.

If the network is communicating and there are IPX hosts, there should be at least one response to the probe for a load host. While this response does not guarantee a download, it is necessary for the download process to progress. Also, after the 7318 has sent its SAP advertisement, you should be able to run the cnsview explore command from the host and see that particular 7318 in the list.

BOOTP Logging

The discover phase handles the preliminary steps of finding an IPX load host, unless one is specified by the set host1 or set host2 command. In the latter case, the discover phase resolves the preconfigured addresses to communicate with the host.

The BOOTP phase is used to determine if the host can download that 7318. For a UDP load, this is the first active phase, since the discover phase is not used for a UDP load. For the BOOTP phase to operate correctly, the following must be true:

For IPX, a load host must have been found.
For IPX, the cnsd.conf file must contain an entry for this 7318.
For UDP, the bootp daemon configuration file must contain an entry for this 7318.
For both cases, the entry in the cnsd.conf or bootp daemon configuration file must specify a valid file, or the 7318 NVRAM must contain a valid host as a result of the set host1 or set host2 command.

If the above criteria are met, the load host responds to the BOOTP request. If the BOOTP request file is null, the BOOTP response specifies the correct file to download. In the UDP download, the BOOTP packet may also have other IP information.

If the BOOTP phase does not get a response, but the discover phase has completed successfully, the host may not have been configured properly, or an incorrect file may have been specified. The BOOTP phase generates a trace similar to the following:

NetLoader - BOOTP 5.0 using IPX
Request file from: levesconte
Received BOOTP reply 
Download file is /usr/lib/cns/cns-s20

TFTP Logging

If the BOOTP phase completes successfully and a load host replies, it is likely that the TFTP phase will complete successfully. If the TFTP request is not honored, there may be a problem with the host. If the file transfer does not complete, there may be a problem with transmission on the Ethernet. The TFTP phase sends a packet similar to the following:

NetLoader - TFTP 5.0 using IPX
Request download of /usr/lib/cns/cns-s20 from: 00000011:000000000001:83A2
Loading VERSION_3.44.1 in format: 5.12 uncompressed

Last block: 2418
Attempt to load config file: /usr/lib/cns/00406e0002db.cfg
Request download of /usr/lib/cns/00406e0002db.cfg from: 00000011:000000000001:83A2
 
Last block: 65

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